1. Field of the Invention
The present invention relates to a slide surface construction, and particularly, to a slide surface construction formed of an aggregate of metal crystals and having a high hardness.
2. Description of the Related Art
Such conventionally known slide surface constructions include an Fe-plated layer, for example, which is provided on outer peripheral surfaces of a land portion and a skirt portion of a substrate made of a steel in a piston for an internal combustion engine for the purpose of providing an enhancement in wear resistance.
However, the known slide surface construction has a problem that under existing circumstances where speed and output of the internal combustion engine have tended to increase, the known slide surface construction is not sufficient in oil retaining property, namely, oil retention and is poor in seizure resistance due to a relatively smooth slide surface thereof.
Therefore, the present applicant has proposed a slide surface construction including a large number of pyramid-shaped metal crystals in a slide surface thereof (for example, see Japanese Patent Application Laid-open No.174089/94).
If the slide surface construction is formed in this manner, adjacent pyramid-shaped metal crystals assume mutually biting states and hence, the slide surface takes on an intricate aspect comprising a large number of fine crests, a large number of fine valleys formed between the crests, and a large number of fine swamps formed due to the mutual biting of the crests. Therefore, the slide surface construction has a good oil retention. Thus, the seizure resistance of the slide surface construction is enhanced.
However, as a result of various reviews of the slide surface construction, it has been made clear that the slide surface construction has a relatively low hardness and hence, in order to accommodate a more severe sliding environment, it is necessary to enhance the hardness of the slide surface construction to inhibit or resist the wearing of the pyramid-shaped metal crystals in such sliding environment, thereby allowing the slide surface construction to maintain a good oil retention.